As more and more digital content is transacted electronically, there is an increasing demand for technologies that can secure the content from unauthorized use and distribution. Unlike physical goods, digital content is easily copied and distributed. The only way to prevent this is for the content provider to establish a trusted environment on the end user's machine that can act as a proxy for securing the content from illegal copying and distribution after it is shipped to an authorized end user.
Cryptographic solutions such as Pretty Good Privacy (PGP) (available from Network Associates) and products available from RSA Security, Inc., secure digital content during its transmission through an untrusted channel, but are inadequate for securing it once it gets to the end user's machine. In fact, the science of cryptography matured during World War II as a means for protecting an untrusted communication channel between two parties that trust each other.
In the present case however, the content provider would generally prefer to not have to trust the end user receiving the content, and so the security of the content must continue to persist even after the digital content has been received by the end user. Furthermore, end users who receive digital content would generally prefer to not be burdened with the security concerns of the content provider simply because they received the digital content. This “last mile” problem cannot be addressed by cryptographic techniques alone, because they require the encrypted document to be converted to clear-text on disk before it can be viewed or manipulated by an application on the end user's machine.
One way to establish a trusted end point on the end user's machine is to force the end user to use a trusted piece of software, namely the content player application, to “play” or process the content. The trusted content player application should be capable of directly processing the digital content in the encrypted format in which it is shipped, so that a decrypted or “clear text” form of the original content is never created on disk.
Another solution is to create a security plugin module that can extend the content player application with the desired security features.